An operating system, sometimes called a supervisor, is a program which supervises and controls the operation of a computer. Operating systems are normally delivered on removable direct access device storage media or on a sequentially organized media that is a backup dump of a running system. In both situations, the receiving hardware must match the sending system exactly in terms of devices containing the system data. Normally, sending systems allow for the device addresses to be one of several alternatives by system generating extra devices. The above restriction requires careful human planning and often extra person weeks in system generation procedures.
Several utilities exist which will dump the contents of a physical direct access storage device to tape and restore the contents to another device of the original type. Examples of these utilities include DDR (DASD Dump Restore service program), a stand-alone program, and IEHDASDR which runs under the MVS Multiple Virtual storage operating system. These utilities all dump and restore from and to single devices (or portions of single devices) and cannot be used to move data from one device type to another.
Several utilities exist which can be used to dump specific data sets from direct access devices to tape and to restore the data sets to direct access devices. IEHMOVE, IEBCOPY and IEBGENER are examples of these utilities which run under MVS. These utilities are designed to allow the transfer of data sets from one device type to another and to process one or more types of data set organization. No utility, however, is capable of addressing all the standard data set organizations and none are capable of dumping a user defined data set organization.
The BACKUP/RESTORE utility will dump and restore the system libraries for the Disk Operating System (DOS). This utility allows for the transfer of these libraries from one device type to another but is restricted to DOS libraries and will not process user data sets.
None of these utilities have the capability of processing all of the data associated with an operating system and its users and allowing the transfer of the data from one device type to another.